About the Authors


Photo of Leo Frishberg

With over 30 years of experience in design—as both a bricks-and-mortar architect and a UX designer—Frishberg drives highly differentiated and innovative solutions. As Principal of Phase II (a UX visioning and strategy consultancy), Frishberg applies Presumptive Design throughout the product lifecycle, from ideation to execution. Prior roles include: Product Design Manager at Intel, where he led multiple UX teams on mission-critical programs and Principal Architect, User Experience for Tektronix’s Logic Analyzer product line, generating several patent filings and spearheading product vision and definition for its next generation of instruments. Frishberg is a Certified Scrum Product Owner.

Over the past 15 years, he has served as Program Chair, Chair, Vice Chair and Treasurer on the board of CHIFOO (Computer Human Interaction Forum of Oregon), the Portland Chapter of SIGCHI.


Charles is a User Experience Designer and Researcher, currently with Intel Corporation, with 10+ years experience in usability engineering, user interface design, behavioral science, research methodology and information visualization. Lambdin’s UX contributions have positively impacted a wide range of projects, from enterprise CRM to executive dashboards to the design of physical workstations. In addition to co-authoring Presumptive Design, Lambdin publishes the “UX Gumshoe” a regular blog about all things UX within the Intel Intranet.

Specialties include: UX research (both qualitative and quantitative), persona development, concept design, prototyping, iterative testing, training, usability engineering, agile UX, information visualization, experimental design.